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Operating instructions
Operation of the QDX transceiver is really simple. There are only three connections:
1. DC Power: use a regulated well-
smoothed DC supply of not more
than 12V; it should be capable of up
to 1A current supply. The connector
is a 2.1mm barrel type (outside
diameter 5.5mm).
2. RF: a standard BNC connector to
your antenna system
3. USB: USB type B connector (a
standard USB type A to B cable is
required) for Audio and CAT control.
Drivers
No additional drivers are required for operation with most Linux distributions, Apple Mac or MS
Windows 10.
For older versions of MS Windows, it may be necessary to install a driver for the serial port
because this driver is not on your computer already by default. This driver is available from the ST
Semiconductor website at
https://www.st.com/en/development-tools/stsw-stm32102.html
applicable to 98SE, 2000, XP, Vista®, 7, and 8.x Operating Systems. There is a description for
installation on Windows 7/8 on the QRP Labs QLG2 page
please check this.
Linux special note
On Linux systems, a particular problem can occur. When the QDX Virtual COM (Serial) connection
is detected, the PC thinks that a modem has been connected and starts trying to send it Hayes
AT-commands dating back to 1981, implemented on Hayes’ 300-baud modem. Yes! 40 years
ago…
The Operating System attempting to send AT commands to your QDX will certainly mess
everything up. Not least because when QDX receives a carriage return character, it will enter
Terminal Applications mode; this will send all sorts of characters back to the PC (as QDX thinks it
is now talking to a terminal emulator) and it will disable CAT command processing, so your PC digi
modes software will not be able to talk to QDX. Disaster.
To fix this you need to issue the following commands to disable ModemManager:
sudo systemctl stop ModemManager
sudo systemctl disable ModemManager
sudo systemctl mask ModemManager
This will permanently stop ModemManager. If for some reason, you actually DO need
ModemManager operational, for some other reason… well there IS a way to stop it just for QDX…
but Google will be your elmer on this!
QDX operating manual; firmware 1_04
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